Ionic liquid-assisted thermal decomposition synthesis of carbon dots and graphene-like carbon sheets for optoelectronic application

For academic research and practical applications, exploration of a facile, low cost, and easy to operate synthesis strategy has become a primarily important work in the development of low dimensional carbon-based nanomaterials. As new members in the family of carbon nanomaterials, zero-dimensional carbon dots and two-dimensional graphene sheets offer many possibilities for extensive applications, especially in the optoelectronic field, but their synthesis processes are somewhat complicated. More challenging is the design and synthesis of carbon dots and graphene sheets that can be directly used in photovoltaics with simple device fabrication processes and low cost. In this work, a novel and easy process route for synthesis of zero-dimensional carbon dots and two-dimensional graphene-like carbon sheets is reported, which relies on direct carbonization of small organic molecules in a liquid-phase by employing ionic liquid as solvent. It is found that the as-prepared carbon material exhibits excellent dispersibility in common solvents, easy film-formation ability and evident photoelectrochemical activity. Meanwhile, the synergistic effect of the carbon dots and carbon sheets for electronic charge generation and transport on their enhanced photovoltaic performance is also explored. It is anticipated that our work may open a new window to facilely prepare novel carbon nanostructures for a wide range of applications.